Metal nanoparticles can melt at significantly lower temperatures than the bulk metal. Metal nanoparticles are highly reactive due to their high surface-to-volume ratios; therefore, they can be melted at lower temperatures and can be reacted to produce compounds with other bonding materials without extensive chemical processing. For example, nano thermite materials such as a mixture of Aluminum and Nickel/Copper oxide nanoparticles can produce a very high temperature and can be reacted in a vacuum. These properties of nanomaterials can be utilized for bonding. The resulting bonds will be thermally efficient, structurally sound, and the joints will be stress free. The assimilated nanoscale materials will assume properties of the bulk material, including its higher melting temperature.
The next generation synchrotron light sources will utilizes many stress- and strain-sensitive components containing bonded dissimilar materials, some of which are critical for efficiency and high-reliability operation of the accelerators and beamlines. Due to lack of strain-free bonding techniques and methods, cooling of high crystal monochromators and mirrors is very challenging and it is often achieved by side or bottom cooling through an indium foil clamped between the optics' surface to be cooled and a copper cooling manifold. However, in order for the monochromator to efficiently diffract x-rays and preserve the incident x-ray beam wavefront, it is extremely important to keep the crystal lattice distortions to a minimum level. Therefore, the magnitude of the clamping force applied to the crystal manifold is generally a compromise between two opposing goals: achieving maximum thermal contact and minimizing mechanical and thermomechanical induced strain, which is detrimental to the performance of the x-ray optics, particularly crystal monochromators. Due to surface roughness and anomaly the contact between sink materials is <10%.
In the design of accelerator and particle physics equipment, it is often necessary to bond small parts of ceramic, glass, or nonmetals to the metals in order to keep them at a low temperature for mechanical stability and to prevent failure. Similarly, high melting temperature metals such as tungsten with copper, or titanium with SS or copper. Glidcop to Glidcop etc. are required to be bonded such a way that produces a curve or bond at the curvature.
The commonly used industrial bonding techniques of brazing or soldering are unsuitable due to the high temperature involved and the resulting strain to the bonded materials. The resulting components end up with a bend in low thermal expansion coefficient (CTE) materials and resulting micro-cracks on the top of surfaces that are required to be undamaged. Moreover, the differences in their CTE can create serious challenges in obtaining structurally and thermally reliable bonds.
Therefore, a need persists to develop a bonding technique that uses nanoparticle and nanofilms at low temperature to enhance the performance of the bond and as well produce curvature after the bonding. The proposed technique would have wide-ranging application in optics, particle physics, military, and various DOE laboratories.